Patients with inflammatory bowel disease often have extraintestinal manifestations (EIMs) involving almost all organ systems, but little has been reported on Achilles tendinitis. Herein, we present a unique case of Achilles tendinitis, which manifested shortly after initiation of mesalazine therapy for ulcerative colitis. A 26-year-old Japanese woman with bloody diarrhea and abdominal cramps lasting for 7 days was referred to our hospital. The Lichtiger clinical activity index (CAI) score was 9 at the first visit. Based on the clinical symptoms and examination results, she was diagnosed with ulcerative pancolitis in the active phase, and treatment with mesalazine (2.4 g/day) and probiotics was initiated. Her symptoms resolved within 7 days of treatment (CAI 3). However, she then developed bilateral Achilles tendinitis without any apparent cause. The Achilles tendinitis subsided with conservative management within 2 weeks, despite continuation of mesalazine therapy. This case instructively suggests that Achilles tendinitis should be noted as an EIM of ulcerative colitis.
Keywords: Achilles tendinitis; Extraintestinal manifestation of inflammatory bowel disease; Mesalazine; Ulcerative colitis.